Bars for supporting the roof in mines and for like purposes



J. T. WALTON Dec. 1, 1959 BARS FOR SUPPORTING THE ROOF IN MINES AND FOR LIKE PURPOSES Filed July 8, 1957 t d eesv Pa to Hugh Wood and Company Limited, Kingsway, Gateshead-on-Tyne, England 7 Application July 8, 1957, Serial No. 670,529 6 Claims. (Cl. 287- -99) This invention concerns bars which are used in substantially horizontal position, in conjunction with upstanding props or the like which hear them, for the purpose of supporting the roof in mines and for similar purposes. It is concerned with that kind of bar which is rigidly provided with a bifurcated joint part at one end and at the other end with a co-related joint part, i.e. adapted to fit into the bifurcated joint part of an adjoining similar bar, the joint parts of the bar first-mentioned being constructed for pivotal connection of the bar to adjoining bars and for the connection thereof to such bars to be made rigid by wedges engaged in mating slots or apertures in the respective joint part-s.

An object of the present invention is to provide an improved construction enabling effective support of a mine or like roof to be obtained, while being adaptable in a desirable way to the restricted space and other conditions met with in mines and similar locations.

Another object of the invention is to provide a bar wherein the joint parts are constructed for pivotal connection with adjacent similar bars on an axis which is offset, with relation to the side of the bar opposite to that to whichlthe load is applied, and the bifurcated joint part has a coupling link pivotally mounted within the bifurcation, while the other joint part of the bar is recessed to receive a similar link of an adjoining similar bar, the pivotal axis of the link first-mentioned being disposed on the opposite side of the longitudinal center line of the bar to the axis firstmentioned and this link and said other joint part being slotted or otherwise apertured for engagement by the appropriate wedges. 1

In order to enable the invention to be readily understood, one embodiment thereof by way of example is illustratedin the accompanying drawing, in which:

Figure l is a plan View showing the bar partly broken away and depicting its connection with an adjacent bar shown fragmentally,

Figure 2 a fragmentary view in elevation on a larger scale than Figure 1 illustrating a completed joint between bars, and

Figure 3 a similar view to indicate one' position of the bars at the start of making joint or' after joint has been released.

The bars shown in the drawings are intended for supporting the roof in coal mines. In Figure l, the bar is marked 1 and an adjacent bar is marked 2. The bar 1 is a straight bar of box section and the joint parts 3, 4 are plugged into the box at its ends as shown dottedat 5 and made rigid with the box part of the bar by welding, as at 6, after known-manner, see also Figures 2 and 3.

According to this invention the bar, comprising thebox part and the jointparts 3, 4 rigid'therewith, is enlarged to one side (ize. the side opposite'to side which takes the load from the mine roof) at the joint parts. The" enlargements are incorporated in the" joint parts 3; 4 and general run of the bar, on the from Figure 1, this joint part is relatively widely bifu rof the two joint parts of the bar should 2 their outline is shown in Figures and 3 wherein they are respectively marked 7, 8. M

Both joint parts of the bar 1 are not, of course, shown in Figures 2 and 3. Only the one 3 is illustrated. The other one 4, however, is similar to' the jointpart shown applied in these figures to what has been termed above the adjacent bar 2. y

The enlargements 7, 8 are holed on an axis offset from the general run of the bar for connection'with adjacent similar roof bars by removable pivot pins Each would suitably have such a pivot pin anchored to it by 'a short chain 10 (Figure 1) or it may be captive in an adjacent joint part. y

The joint part hereinbefore referred to asthe bifurcated joint part is the one marked 3. As will be understood cated by vertically slotting it, the nature of slotting within the bifurcation being further indicated by dotted line 11 in Figure 2. This slotting is extended inwardly along the bar onthe side of the bar opposite to the adjacent enlargement 7, anfdin this extended slot part is the pivot 12 'of a short coupling link 13. The latter normally rests at a slight inclination outwardly and downwardly on a shallow H inner side 15 of the vertical slot and the bottom 16 of the extended slot part as shown in Figure 3. In thenormal position, the link extends outwardly for a short distance from the vertical slot as also shown in Figure il. Towards its outer or nonspivotal end, which is rounde'd semi-circularly, it is formed with a slot 11 which may be parallel-sided as shown or slightly widened from its outer to its inner extremity. The tail "of the link 13 at the pivot is bossed at 18" andth'e boSsiHgsquared-otE at, 19,

to form a stop for engagement with the bottom 16 of the extended slot part which is slightly inclined, inwardly and downwardly of the bar, with respect to tudinal center line of the bar.

The joint part hereinbefore referred to as the other" joint part is the one marked 4. It is disposed at the other end of the bar and is recessed at 20 to receive, with slight clearance, the major part of the coupling link of an adjoining similar bar and the recess extends inwardly along the bar for afai'r distance the opposite side of the bar to the adjacent enlargement as will be understood from Figures 2 and 3. V The sides'of the recess are formed with parallel-sided slots21 disposed parallel to the center line of the bar. 17 of the coupling link 13 of an adjoining similar bar. The ordinary form of wedge used with bars of thekind described, can be employed in the present invention for,

insertion in the mating slots of adjoining bars. Such-a wedge, shown at 22, would suitably be anchored bar by a short chain 236 (Figure 1).

made with an adjoining bar, the two pivot the wedge 22 lie substantially at the of an inverted isosceles triangle having its apex at the pivotal axis between the two bars (cf. Figure 2). Suit ably, the slot 17 in the coupling link and the slots ,Zl ln the joint part 4 at the other end of the bar are longer than the effective width of the wedge, so that the latter bears on the outer end of the coupling-link slot 17 and the outer end of the slots When joint pins 9, Hand by curving it round in front joint part, as shown at 23in vFigures 2 and 3, to provide position when joint is made between bars. realised that it is important that the slotting and recessing be such that the coupling link 13 on one joint part 3 of the bar may rest Patented Dec. 1 teas charnfer 14 between the the longi-v Th'ese slots arefor mating withjth e slot to each" angular points- 21 in the recessed joint part 4. In the latter, the recess 20 is continued outwardly of. the pivot pin hole of such in'a suitable position to be picked up by the shaped recess 20, 23 in the other joint part 4 of a companion similar bar, as the latter is swung up on its pivot 9 from a position such as is shown in Figure 3, and thereby carried automatically into position for insertion of the wedge.

It may be observed that the design of the joint parts of the bar thus described, is such that when two of the bars are substantially horizontally supported at each side of the joint between them, as by props such as 24 in a coal mine, the joint has only a limited downward deflection before locking and assuming rigidity to resist roof movements. However, either bar may pivot freely downwards when the support or prop for that bar is absent or removed and the wedge 22' is removed or is not in place as will be understood from Figure 3. Thus, free downward pivoting from the horizontal of a bar can be effected at either forward or face end or goaf end of a bar in place in a coal mine working. Moreover, the

construction allows a bar to be connected to a bar already in use by raising it substantially vertically from below, or slightly back (as in Figure 3), and inserting the appropriate pivot pin 9. In this operation, the surface 15 within the bifurcation of the joint part 3 of the last-mentioned bar may serve as a rest for the tip of the companion joint part 8 of the other bar (cf. Figure 3) so as to facilitate alignment of the holes in the joint parts to receive the pin 9, or in other words it assists in effecting the pinning at '9. The bar thus pinned may then be left hanging until required for use. The bar of the invention also provides a high initial resistance to deflection when the bar is loaded unsupported except for its connection cantilever fashion to an adjoining supported bar because the effect of placing the upper half of the bar in tension by the load above is transmitted directly through the joint mechanism to the supported bar. An amount of travel can be allowed to the wedge to permit of a limited upwards or downwards movement of a bar to follow reasonable irregularities of the roof. In this connection, the inclined part 16 of the surface 11 aforesaid cooperates with the stop surface 19 of the coupling link 13 to define a limit of upward swing of a bar pivotally connected to a bar already in position at the roof. If a forward bar, previously used cantilever fashion conuected to a supported bar, is in turn supported by a prop on advance of the coal face, the tapered wedge may be withdrawn to allow flexibility in the joint for efficient tight setting of the props, a slight play being possible between the end of the recessed joint part 4 and the bottom wall part 15 of the vertical slot in the companion joint part 3 of the supported bar. When a support (prop) at F the goaf side of a mine working and the wedge at the joint there are withdrawn, a bar thus released of its support will swing freely downwards to a vertical position and can be removed on removal of the pivot pin of the bar, so that this bar is completely freed. Though the bar described is of what is termed non-reversible type, i.e. can only be used one way up in a roof, it can be made in steel of reasonably small proportions and thus be not unduly heavy, though of sufiicient capacity for roof supporting purposes in coal mines and similar situations. In addition, the free pivoting of the bar possible on assembly or release of the bar in or from working position provides for considerable convenience in the restricted spaces of, and operating conditions in, coal or other mines.

It will be understood that the invention is not restricted to the particular construction of bar above described and illustrated in the drawing. For example, it is not essential that the bar be of box section between the joint parts 3, 4 because this part of the bar could be of H or any other suitable section; also the joint parts referred to may be made integral with the remainder of the bar, instead of making them separately and welding them in position on the bar.

,I claim:

1. A bar for supporting the roof in a mine, said bar comprising a bifurcated joint part at one end and a corelated joint part at the other end, said joint parts both being holed for reception of respective pins to provide pivotal connection of the bar with adjoining similar bars on axes which are offset on the side of said bar opposite to that to which the load is applied, and a coupling link captive within the bifurcation of said bifurcated joint part and pivotal on a fixed axis which is disposed on the opposite side of the longitudinal center line of said bar to the first-mentionedaxes, said co-related joint part being formed with a recess to receive between the sides of the recess the free end of the similar coupling link of an adjoining similar bar already in position at the roof, and the free end of the first-mentioned coupling link and said co-related joint part having respective wedge apertures for reception of wedges for rigidising the connection of the bar with adjoining similar bars having similarly apertured link and joint parts, said bifurcated joint part hav ing within the bifurcation a surface on which the coupling link within the bifurcation can normally rest at a slight inclination outwardly and downwardly of such joint part and'said co-related joint part having within its said recess a cam surface co-operative with the said similar coupling link of said adjoining similar bar in such a manner that, when the bar is pivotally connected at said co-related joint part to said adjoining similar bar at a respective pin aforesaid and is raised from a depending position, said cam surface moves against the coupling link of said adjoining similar bar and raises it about its fixed pivotal axis to facilitate alignment of the respective wedge apertures of this link and said co-related joint part to receivev a wedge.

2. A bar according to claim 1, wherein the bifurcation.

of the bifurcated joint part of said bar has a substantially vertically disposed surface within it which, when said bar is in position in a roof, is operative as a hearing or rest surface for the co-related joint part of a similar bar in a manner to assist pivotal connection of the bar in depending position with that first-mentioned by a pin.

3. A bar according to claim 1, wherein the bifurcation of the bifurcated joint part of the bar has within it a surface which is slightly inclined inwardly and downwardly and the tail end of the coupling link pivotally mounted within the bifurcation has a stop surface cooperative with the surface first mentioned to define an upward limit of pivoting of an adjoining similar bar on said bar.

4. An articulated joint for mine roof bars, comprising a bifurcated joint part on one end of a first bar and a corelated joint part on one end of a second and similar bar, said joint parts both being holed for reception of a pin to provide pivotal connection between said bars on an axis which is offset on the side of the bars opposite to that to which the load is applied, and a coupling link captive within the bifurcation of said bifurcated joint part and pivotal on a fixed axis which is disposed on the opposite side of the longitudinal center line of said first bar to the first mentioned axis, said corelated joint part being formed to engage within said bifurcated joint part and to co-operate laterally with the free end of said coupling link, this free end and the co-related joint part having alignable apertures for reception of a wedge for rigidising the joint, said bifurcated joint part having within the bifurcation a surface on which said coupling link r can rest at a slight inclination outwardly and downwardly of such joint part and the co-relatecl joint part having a cam surface co-operative with said coupling link in such a manner that when said first bar is in position up at the roof and pivotal connection between the two bars has been effected by said pin, the raising of the second bar from a depending position causes said cam surface to move against said coupling link and raise it about its fixed pivotal axis to facilitate alignment of said alignable apertures for reception of said wedge.

5, An articulated joint for mine roof bars according to claim 4, wherein the bifurcation of the bifurcated joint part of the first bar has a substantially vertically disposed surface within it operative as a bearing or rest surface for the co-related joint part of a similar bar in a manner to assist pivotal connection of the latter bar in depending position with said first bar by a pin.

6. An articulated joint for mine roof bars according to claim 4, wherein the bifurcation of the bifurcated joint part of the first bar has within it a surface which is slightly inclined inwardly and downwardly and the tail end of the 1 References Cited in the file of this patent FOREIGN PATENTS 499,766 Belgium Mar. 31, 1951 Great Britain Aug. 4, 1954 

